Dr. Robert Chiu's research focuses on the function of retinoblastoma (RB) associated proteins in controlling cell growth and differentiation, the function of mitogen-activated protein kinase (MAPK) phosphatase in a pathological state and the mechanisms of drug-induced gingival overgrowth.
Chiu's current work on RB associated proteins focuses on mechanisms of cyclophilin A (CypA) in neuronal development and differentiation. Using RNA interference and its rescue not only reveals a novel function of CypA in the processing of retinoic acid-induced neuronal differentiation of p19 cells, it also suggests an important technique in controlling gene expression as a temporal fashion.
Work on Jun N-terminal kinase (JNK) specific MAPK phosphatase (MKP) focuses on the 12-O-Tetradecanoylphorbol-13-acetate (TPA)-induced orthovanadate-sensitive phosphatase involved in the regulation of TPA-inducible JNK activity in immortalized and transformed epithelial cells. Such changes in the normal signaling system may result in uncontrolled cell growth and differentiation. Thus, delineation of alteration of signaling components should advance understanding of the molecular mechanisms involved in the development of human cancers.
Chiu and his colleagues also have recently studied the mechanism of drugs such as cyclosporin and phenytoin-induced gingival overgrowth. Their data suggests that gingival overgrowth is due to the increased synthesis of collagen concurrent with decreased degradation of collagen in the gingival tissue. CsA-induced oxidative-stress is also involved in the regulation of signaling and results in the disruption of the steady state of extracellular matrix levels.
Sun S, Wang Q, Giang A, Cheng C, Soo C, Wang CY, Liau LM, Chiu R. Knockdown of CypA inhibits interleukin-8 (IL-8) and IL-8-mediated proliferation and tumor growth of glioblastoma cells through down-regulated NF-kappaB. J Neurooncol. 2011 Jan;101(1):1-14. Epub 2010 May 9.
Calhoun CC, Lu YC, Song J, Chiu R. Knockdown endogenous CypA with siRNA in U2OS cells results in disruption of F-actin structure and alters tumor phenotype. Mol Cell Biochem. 2009 Jan;320(1-2):35-43. Epub 2008 Aug 14.
Wang Q, Zheng JY, Kreth J, Yan X, Kamata M, Campbell RA, Xie Y, Chiu R, Berenson JR, Shi W, Chen IS, Pang S. Regulation of prostate-specific antigen expression by the junctional adhesion molecule A. Urology. 2009 May;73(5):1119-25. Epub 2008 Jul 7.
Jin C, Kato K, Chimura T, Yamasaki T, Nakade K, Murata T, Li H, Pan J, Zhao M, Sun K, Chiu R, Ito T, Nagata K, Horikoshi M, Yokoyama KK. Regulation of histone acetylation and nucleosome assembly by transcription factor JDP2. Nat Struct Mol Biol. 2006 Apr;13(4):331-8. Epub 2006 Mar 5.
Song J, Pang S, Lu Y, Yokoyama KK, Zheng JY, Chiu R. Gene silencing in androgen-responsive prostate cancer cells from the tissue-specific prostate-specific antigen promoter. Cancer Res. 2004 Nov 1;64(21):7661-3.